Officials in Afghanistan say a suicide car bombing Sunday in southern Helmand province has killed 11 people and wounded a dozen more.

A provincial spokesman says 10 police officers and a child were killed in the blast near police headquarters in the city of Lashkar Gah. He said three civilians were among the wounded.

The Taliban has claimed responsibility for the attack.

Security for Lashkar Gah was handed over this month from foreign to Afghan forces, part of the first stage of a plan to have all of Afghanistan under the oversight of Afghan security forces by the end of 2014.

The attack comes on the second day of a visit to Afghanistan by the top U.S. military officer. Admiral Mike Mullen has been meeting with commanders and troops in the south, a region that has been rocked by violence in recent weeks.

Mullen said Sunday the new U.S. commander in Afghanistan is working on plans to withdraw 10,000 U.S. troops from Afghanistan by the end of the year. Mullen said Marine Corps General John Allen has until mid-October to submit his plan.

Military officials say the design of Allen's withdrawal plans may hinge on whether the latest surge in attacks continues through the holy month of Ramadan, which starts Monday.

In eastern Afghanistan, NATO says one of its service members was killed Sunday in a bomb blast.